This invention relates to a system and method for lifting and supporting a building, and, more particularly, to such a system and method in which the foundation or concrete slab of a building is lifted and supported in its raised position by a plurality of pilings.
Houses and other buildings are often erected on foundations, or concrete slabs, which are not in direct contact with load supporting underground strata, such as bedrock, or the like. If not initially constructed properly, or if soil conditions change, the foundation footing may settle, causing the foundation or slab to sag and/or crack. Unless the building is supported, or shored, continued settling may result in major structural damage or collapse of the building.
There have been several suggestions in the prior art for raising and supporting the foundation or slab of a building of this type. For example, according to one technique, beam members, or the like, are placed underneath the foundation and lifted to raise the foundation. However, this requires significant excavation of the ground area around the foundation which is very time consuming and labor intensive. Also, according to some of the latter techniques, the foundation or slab is lifted, or jacked up, and pilings are inserted underneath to support same. However, the pilings are often not directly supported on the bedrock, resulting in continued settling after the pilings are in place. Further, in many instances, the pilings are visible above the basement floor.
In still other prior art techniques utilizing pilings, a single hydraulically actuated system is used to drive each piling, requiring the use of a relatively high hydraulic pressure system which is expensive and cumbersome to use. Also, in these systems it is difficult to apply a symmetrical load along the axes of the pilings which is essential to avoid undue stresses and strains on the pilings.
Therefore, what is needed is a foundation lift and support system in which the pilings are supported on bedrock, and a symmetrical, stabilized, coaxially-directed load is applied to the pilings requiring minimal excavation and relatively low hydraulic lifting pressure.